Repeat demand SMS's to incorrect number

Incredibly *********** company. I keep receiving SMS's from them telling me to pay into some Standard Bank account; I have NO Standard Bank accounts! It appears someone (I have the name) has given my cell phone number to them as their own, possibly because they are a delinquent payer. I have contacted them by phone on many occasions requiring they remove my number as this person's contact number, yet I have just received another demand SMS!